All of us here are interested in new worlds and aware how complicated it is to make hospitable planets with stable orbits. The Kepler Mission website has a really neat planetary system simulator where you can hone planetbuilding skills:

Very interesting stuff! This definitely gives a great deal of isnight into all the factors that go into the creation and conditions of individual planets, not to mention solar systems and the forces that hold them together. I'm decidedly not a scientist, but one could go on for some time about the features presented here.

Perhaps it's easy to make planetary systems after all! The Spitzer space telescope discovered that accretion disks exist around most binary systems, as long as the two stars are either very close or very distant. Since more than half the stars are binaries, this changes the numbers in the Drake equation yet again and increases the odds for extraterrestrial life. Here's a link, with a nice diagram and a rendition of a double sunset: Stellar twins

As the saying goes: (Science) fiction must be plausible. Reality is under no such constraints! (*laughs*)

For I come from an ardent raceThat has subsisted on defiance and visions.

Very cool. I think a 100 AU binary system would be a pretty cool setting for a scifi story. You could have fun with a divided evolutionary lineage if you played your cards right... Can you say sibling rivalry?

We spoke of the creation of planetary systems, but there are other forces that will overpower the relatively local phenomena.

Most galaxies are rushing away from each other, with a few exceptions of gravitationally bound systems. One of the latter is our nearest neighbor, the Andromeda galaxy. In about two billion years, while the sun still has not entered its red giant phase, Andromeda will do its first close pass. There will be few, if any, direct star collisions -- but the gravity disturbances will disrupt planetary systems, including ours. In the end, both galaxies will lose all their intergalactic dust and settle into elliptical shape.

A breathtaking series of pictures by James Gitlin shows how this will play out in our skies, although there won't be any observers left (or if there are, they'd better have fast spaceships and/or stable wormhole generation technology). Here is one image, and a link, which also has a video of the merger: Galactic collisions. The animation and more images are halfway down the page.

Image by James Gitlin, of the Space Telescope Science Institute

For I come from an ardent raceThat has subsisted on defiance and visions.